1. Field of the Invention
The present invention relates to testers, and particularly to a voltage variance tester.
2. Description of Related Art
A typical microprocessor-cored computer system, such as a personal computer or a workstation computer, is turned on and off by a switch device that mechanically connects/disconnects a power supply of the computer system to/from an external voltage source, such as AC 110V. The power supply is connected to the external voltage source and transforms the external voltage into a predetermined DC level, such as +3.3V, ±5V and ±12V, and the computer system is turned on to perform various programs and functions.
As known by a person skilled with computers, power supplies are typically either ATX power supply or BTX power supply. A motherboard of a computer can be coupled to the BTX power supply via a 24-pin BTX power connector. The BTX power supply provides +3.3V, ±5V, ±12V, +5V_STBY (stand by), PS-ON (power supply on) signal and PWROK (power ok/power good) signal to a motherboard of the computer. However, each type of power supply has a unique voltage variance/range centered about its rated output; therefore operators need to test a voltage variance of the motherboard corresponding to the power supply output to make sure the motherboard is compatible with that type of power supply.
What is needed, therefore, is a voltage variance tester which can test voltage variance of a motherboard.